The Fluid Mosaic Model of chromatin organization: integrating dynamics, conformational heterogeneity and multiscale organization

The field of 3D chromatin organization has advanced significantly in recent years, with a marked increase in research focusing on dynamics and viscoelastic properties of chromatin. The hierarchical model of chromatin organization, which spans from nucleosomes to loops, domains, compartments, and territories, has long been the standard framework for understanding chromatin structure. While this model successfully explains many aspects of chromatin organization, it falls short in explaining the dynamic aspects of chromatin. To capture the complexity of chromatin behavior, it is crucial to have a model that integrates both its structural organization and its dynamic properties. Similar to cell membranes, chromatin organization appears to be both mosaic and fluid, characterized by multiscale organization, conformational heterogeneity, and dynamic behavior. Adopting the fluid mosaic model for chromatin would offer a more comprehensive understanding of its functions, accommodating its complexity and dynamic nature. The Fluid Mosaic Model, previously used to describe membrane structure and dynamics, is proposed here to explain the complex structural organization and dynamics of eukaryotic chromatin.